Scanning light microscopes have been known for several decades. Their functional principal is based on a light beam being concentrated to a small point of light (the first focal point) on a sample. The sample and this point of light are mutually moved in such a way that a specific area of the sample is scanned by the point of light. The light which penetrates the sample or is reflected by it and/or the fluorescence triggered on or in the sample during the scanning is therefore referred to as “light originating from the sample” and is measured by one or more photodetectors. An enlarged image is produced in that an original measurement point is assigned a specific area on an image of the sample. In principle, such a scanning light microscope therefore includes: a light source, such as a laser, which produces a light beam; a sample holder for holding the sample; an optic for producing a first focal point on the sample; an optical arrangement for imaging a second focal point using the light which shines through the sample and/or is reflected by the sample and/or which represents fluorescence triggered on or in the sample; a photodetector for measuring the intensity of the second focal point; and a scanning mechanism for mutual movement of the sample and first focal point.
The approach has a number of disadvantages. First, the small focal point means that only a very small portion of the sample can be addressed at one time. Second, the necessity for moving the light creates significant engineering issues and increased cost.